THE KANSAS UNIVERSITY 

 SCIENCE BULLETIN. 



Vol. IX, No, 10.] DECEMBER, 1914. [vI ho xi\ s nTio 



A Study of the Dimensions of the Chromo- 

 somes of the Somatic Cells of 

 Ambystoma. 



JAS. B. MACK. 



Contribution from the Zoological Laboratory No. 212. 

 [Submitted as a partial fulfillment of the requirements for the degree of Master of Arts.] 



FOR several years past cytologists have devoted much time to 

 the study of the chromosomes of the germ cells, the most 

 thorough work having been done upon the Insecta, while some 

 has been done upon the Amphibia. But to my knowledge scarcely 

 any investigation has been attempted upon the chromosomes of 

 somatic cells. 



It is the purpose of this paper to present some results obtained 

 from the study of the somatic cells of Ambystoma in an attempt 

 to discover the relation between the chromosomes of cells of the 

 derivatives of the mesoblast and those of the ectoblast. The 

 work along this line was suggested to the author by Dr. C. E. 

 McClung and we have hoped that we might obtain some data 

 which might aid us toward the establishment of a correlation of 

 individual chromosomes and definite somatic characters. ■ 



Since the work was begun, however, a paper has appeared by 

 Capt. C. F. U. Meek on "A Metrical Analysis of Chromosome 

 Complexes" in which he draws the conclusion that chromosomes 

 of different phyla possess diameters of constant size, and all those 

 above Nemathelminthia have a diameter of .83,", and that the 

 somatic chromosomes are identical with those of the germ cells. 

 This has led me to conduct my investigations along a somewhat 

 different line from that which I originally intended in order to 



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 2 —Univ. Sci. Bull., Vol. IX, No. 10, 



